Furnace question for Mete

Kit Carson

Kit Carson

Joined
Oct 6, 1998
Messages
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Not wanting to hijack KindOfBlues oven thread, so,

Mete, tell me why I would be better off with a vacuum furnace?

fwiw, I spent alot of time looking for one several years ago and you are right, they are expensive.
 
With a vacuum furnace you won't get any scale and they are made with precision controls. The one listed of course drops the metal directly into the oil when ready. Something to dream about.
 
Hmmm,
I've studied this quite a bit and came to the conclusion that since I mostly work with steels that are air (or Alu press) quenched, the oil quench thing wouldn't be a big asset.
Same thing on the vacuum chamber. To me, pulling a blade out of a hot vacuum oven is the same as pulling it out of a hot foil pouch. When the outside air hits it you get the same result. I don't get any scale with foil wrapped blades and very little discoloration if I quench them in the foil.
I'm very happy with the Sentry controller for accuracy and check it about every three months.
I would like to have one of the Cress systems with the high heat furnace on top and tempering oven on bottom. Haven't been able to find one of those surplus at a decent price though. New ones are way to $$$.
 
Kit, what a great thread you opened up. My first thoughts about this type furnace were, I think, a little different than yours but not more essential than your thoughts.

Mete, I have two sophomoric questions: in dropping straight from oven into quenching media would that tend to eliminate warp of the thickness steel we usually HT or promote warp, and do these quenching tanks agitate the media or does the steel drop into a deep enough quiescent bath ? My foremost impression of this type setup was in hitting that all precious nose that I read so much about here.


I realize Kit grinds after HT so the warp part of my question would not effect him as much as it does others, such as me.

RL
 
Can't small time producers get the same effect with high temp salts? No oxygen environment, that is.

I don't for 2 reasons:

1) I don't have the knowledge to set one up.
2) Sounds really dangerous


Do they use high temp salts in mass production? Or is it all vacuum ovens?

Steve
 
Steve, the reason I do not pursue that is the salt will ruin my electric oven elements. I was told that with enough money I could get a salt pot for use in the oven.
 
Warping is minimized by proper preparation such a s normalizing and proper quenching that is point down or edge down. Vacuum itself would not effect warp.....High temp salt is definitely used in mass production including knives.Kevin Cashen uses salt for HT.
 
For me, salt is a no go after a period of hard coat anodizing (salts) my son and I had a few years ago. Salt does bad things to metal equipment and my shop isn't set up to deal with that. As I understand it, HiTemp salts are much more difficult to use.
I've had engraved knives salt bath treated and they came back beautiful, so it is interesting.
I'll just stick with heat treating foil, Alu press plates, and the Paragons. It ain't broke so I don't need to fix it, I reckon :)
 
So my warp question is basically answered since your responce seems to indicate that the steel in such a contraption would not just fall willy nilly into the quench (?)
 
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